1. Field of the Invention
The present invention relates to a particle detector and a particle analyzing apparatus. More particularly, the present invention relates to an improved particle detector for detecting the number, the size, and the like of particles in a particle-containing specimen by means of a flow cell and to an improved particle analyzing apparatus for analyzing particles in a particle-containing specimen by means of a flow cell.
2. Description of the Related Arts
Flow cells for analyzing particles in a sample are disclosed, for example, in Japanese Laid-open Patent Application (Kokai) Nos. Sho 60(1985)-262041 and Sho 61(1986)35333.
In analyzing particles contained in a whole blood sample by means of a known flow cell, three kinds of diluted specimen, namely, a specimen for measuring leukocytes, a specimen for measuring erythrocytes plus platelets, and a specimen for measuring hemoglobin, are prepared out of the whole blood sample so as to measure the number of leukocytes, the number of erythrocytes plus the number of platelets, and the concentration of hemoglobin, respectively in detecting sections each fabricated exclusively for measuring one of the above three kinds of specimen.
The dilution ratio of these three kinds of diluted specimen is, in the case of measuring leukocytes, about 200 to 500 times when a sheath flow is not used, and is about several to 50 times when a sheath flow is used. In the case of erythrocytes plus platelets, the dilution ratio is about 25000 to 50000 times when a sheath flow is not used, and is about 200 to 1000 times when a sheath flow is used. For measuring hemoglobin, the dilution ratio is about 200 to 500 times.
Here, a lot of blood will be required if a specimen is to be diluted in a ratio of about several to 50 times. On the other hand, two diluting steps will be required if a specimen is to be diluted in a ratio of about 25000 to 50000 times.
The two purposes, namely, the reduction of the amount of blood and the simplification of the diluting steps cannot be achieved at a time in a conventional apparatus if the measurement of leukocytes and the measurement of erythrocytes plus platelets are to be carried out in a single detecting section, so that one of these measurements has to be sacrificed. Therefore, two detecting sections are generally provided for carrying out the measurements in the respective detecting sections. This, however, leads to complication of the apparatus and increase in the costs.